Nanoflower-shaped ultraviolet photodetectors

Researchers
have synthesized nanoflower-shaped structures of gallium nitride that can be
used to make ultraviolet photodetectors1,to be used in
the fields of space, military and biology as detectors and sensors.

Self-powered photodetectors produce current in
the external circuit proportional to the intensity of incidental light, and
detect optical signals. Their performance strongly depends on the material and
active area of the device.Existing photodetectors made of silicon semiconductor
cannot efficiently
detect ultraviolet light.

To improve
efficiency, scientists led by Govind Gupta from the CSIR-National Physical
Laboratory in New Delhi made the photodetectors by depositing nanoflower-shaped
gallium nitride ona silicon substrate. They then tested the photodetectors by
bathing them in ultraviolet light.

The
photodetectors exhibited increased light absorption which, in turn, created a light-induced
current. The detectors were highly sensitive and showed fast response even when
incident optical signals were weak.

Since the
photodetectors did not rely on an external power source, they are energy-efficient
and cheap to use.

“The
photodetectors were able to detect ultraviolet light within milliseconds,
making them potentially useful for monitoring solar ultraviolet light,” says Gupta.